Terminal and wrapped wire assembly

ABSTRACT

A number of wires are wrapped about a terminal. An insulationfree section of a first wire is initially wrapped about the terminal with a relatively low number of turns, e.g., two, leaving a short end portion which is directed axially along the terminal. The end portion of the first wire is then bonded to the terminal, the bonding operation compacting the end portion. Next, an insulation-free section of a second wire is wrapped about the terminal with a relatively low number of turns, e.g., two, overlapping the bonded and compacted end portion of the first wire, leaving a short end portion which is directed axially along the terminal. The end portion of the second wire is then bonded to the terminal, the bonding operation compacting the end portion. Additional wires may next be added successively in like, overlapping manner. A strong, compact terminal and wrapped wire assembly is formed by this method.

United States Patent Cushman 51 May 16,1972

[54] TERMINAL AND WRAPPED WIRE ASSEMBLY Robert Holbrook Cushman, LowerMoreland Township, Montgomery County, Pa.

[ 72] Inventor:

[73] Assignee: Western Electric Company Incorporated,

New York, NY.

[22] Filed: Apr. 16, 1971 [21] Appl. No.: 134,808

3,088,087 4/1963 Colten ..339/276 A X Primary ExaminerDarrell L. ClayAttorney-W. M. Kain, R. P. Miller and R. C. Winter 57 ABSTRACT a Anumber of wires are wrapped about a terminal. An insulation-free sectionof a first wire is initially wrapped about the terminal with arelatively low number of turns, e. g., two, leaving a short end portionwhich is directed axially along the terminal. The end portion of thefirst wire is then bonded to the terminal, the bonding operationcompacting the end portion. Next, an insulation-free section of a secondwire is wrapped about the terminal with a relatively low number ofturns, e.g., two, overlapping the bonded and compacted end portion ofthe first wire, leaving a short end portion which is directed axiallyalong the terminal. The end portion of the second wire is then bonded tothe terminal, the bonding operation compacting the end portion.Additional wires may next be added successively in like, overlappingmanner. A strong, compact terminal and wrapped wire assembly is formedby this method.

10 Claims, 3 Drawing Figures Patented May 16, 1972 N m g T% PM wu q w s5 W w Q Background of the Invention This invention relates to a terminaland wrapped wire assembly and, more particularly, to a terminal andwrapped wire assembly in the form of a terminal about which a number ofwires are compactly wrapped.

In the art of joining wires to a terminal or other elongated member, itis known to wrap one or more wires about the terminal. The terminal tobe wrapped is normally of multi-cornered cross section in order toeffect a firm anchoring of each wrapped wire. Lengths of wire areselected so as to provide several side-by-side turns of each wrappedwire. A conventional wire wrapping tool wraps the entire selected lengthof each wire about the terminal. Typically, wire lengths are selectedsuch that at least four or five turns may be wrapped, in order to securethe wire. firmly about the multi-cornered terminal. This number ofturns, while affording sufficient strength and durability to eachwire-to-terminal interconnection, requires the use of a fairly longaxial portion of the terminal for each wrapped wire. The number of wireswhich may be joined to any given axial length of terminal is, thus,severely limited.

It is also known to bond to an elongated member a wire or strand whichhas been wrapped about the member. Typically, the wire is bonded to themember at the wrapped section of the wire. This furnishes a more rigidand secure assembly than that which is present when only the wirewrapping operation is employed. However, it has been found that thewrapped and bonded structure, as described, incorporates undesirablyhigh stress concentrations in the area of the wrapped and bonded wire,making it desirable to provide some manner of strain relief to theassembly.

SUMMARY OF THE INVENTION An object of the invention resides in new andimproved terminal and wrapped wire assemblies.

The invention contemplates the wrapping of a relatively short section ofa first wire about a first axial portion of a terminal, the wrappingtypically utilizing about two turns of wire. Another section, such as ashort end section, of the first wire is directed axially of the terminalalong a second axial portion of the terminal, preferably immediatelyadjacent to the first axial portion of the terminal. The end section ofthe first wire is then affixed or bonded to the second axial portion ofthe terminal, a preferred manner of affixation involving applyingsufficient bonding pressure and heat to the end section to compact andbond the end section to the terminal. A significant degree of strainrelief is provided to the wrapped section of the first wire by virtue ofthe fact that bonding occurs only at the end section of the wire and notat the wrapped section. The affixation of only the wire end section tothe terminal also permits the wrapping of the wire about a terminal ofcircular or other comer-free cross section, since the wire-to-terminalbond at the wire end section will obviate any need for an anchoringeffect to occur along various corner surfaces of the terminal.

A relatively short section of a second wire is next wrapped overlyingthe bonded and compacted end section of the first wire immediatelyadjacent to the wrapped section of the first wire. The wrapped sectionof the second wire acts to secure and protect the bonded and compactedend section of the first wire. Once again, only approximately two turnsof wire are required for the wrapping of the second wire about thesecond axial portion of the terminal and over the end section of thefirst wire. An additional section, such as a short end section, of thesecond wire is directed along a third axial portion of the terminal. Theend section of the second wire is then affixed or bonded to the thirdaxial portion of the terminal, the bonding pressure and heat once againpreferably compacting the bonded end section. Additional wires maythereafter be wrapped and bonded in like manner. A wrapped wire andterminal assembly will result, wherein a relatively high density ofsecurely and durably attached wires results.

BRIEF DESCRIPTION OF THE DRAWING FIGS. 1-3 of the drawing are isometricviews illustrating three successive stages in the formation of aterminal and wrapped wire assembly in accordance with the invention.

DETAILED DESCRIPTION Referring initially to FIG. 1, an electricallyconductive wire 11 may be covered with a layer of insulation 12. Allinsulation covering has been stripped, however, or is otherwise absentfrom a length of the wire 11 which is to be joined to a terminal 13. Anumber of other wires are also to be joined to the terminal 13, asdepicted in FIGS. 2 and 3. The terminal 13 is an elongated, electricallyconductive member which may have a cross-sectional shape, e.g., square,furnishing a number of corners about which each wire may anchor upon awrapping of the wire around the terminal. Alternatively, the terminalmay be of circular or other comer-free cross section.

In order to join the wire 11 to the terminal 13, a short section of theinsulation-free length of the wire is first wrapped about an axiallyextending portion of the terminal, for example, through the use of aconventional wire wrapping tool (not shown). The section of the wirewrapped about the terminal 13 is spaced from an end section 14 of thewire 11. The number of turns of wire which are wrapped about theterminal is relatively small, typically from one to three turns andpreferably approximately two full turns of wire.

The end section 14 of the wire 11 constitutes a short tail segment whichis directed axially of the terminal 13 along an axial portion of theterminal immediately adjacent to the axial portion of the terminal aboutwhich the short section of the wire has been wrapped. In order to securefurther the wire 11 to the terminal 13, the end section 14 of the wireis now attached to the terminal by a bonding operation. The bonding ofthe end section 14 to the terminal 13 also permits a relatively loosewrapping of the wire 11 about the terminal, lessening stresses in thewrapped section of the wire. Bonding preferably acts to flatten orcompact the end section 14, as shown at 16, while affixing the endsection to the terminal. Mechanical thermal pulse bonding, as describedin application Ser. No. 701,185, filed by applicant on Jan. 29, 1968 andnow abandoned, conventional thermocompression bonding, or any othersuitable bonding or affixing operation may be employed.

A second wire 17 (FIG. 2) is next joined to the terminal 13 in similarmanner to the joining of the first wire 11. A short insulation-freesection of the wire 17, spaced from an end section 18 of the wire, iswrapped about the terminal. The short section of the second wire 17 iswrapped so as to overlap the bonded and compacted end section 14 of thefirst wire 11 and occupy the axial portion of the terminal 13immediately adjacent to that occupied by the short wrapped section ofthe first wire. Both axial and radial structural compactness is providedby the flattening of the end section 14 of the first wire 1 l and thenthe wrapping of the second wire 17 over the flattened end section andimmediately adjacent to the short wrapped section of the first wire.Once again, relatively few turns of wire, preferably two turns, areutilized to form the short wrapped section of the second wire 17.

The end section 18 of the second wire 17 constitutes a short tailsegment which is directed axially of the terminal 13 along an axialportion of the terminal immediately adjacent to that about which theshort section of the second wire has been wrapped. In similar manner tothe afiixing of the end section 14 of the first wire 11 to the terminal13, the end section 18 of the second wire 17 is affixed to the terminal,for example, by bonding with sufficient pressure and heat to flatten orcompact the end section at a bonding location 19.

In like fashion, a third wire 21 (FIG. 3) may next be joined to theterminal 13 by wrapping a short section of the third wire overlying theend section 18 of the second wire 17 and then affixing an end section 22of the third wire to the terminal by compression bonding. Any number ofadditional wires may be added in like manner, as illustrated in FIG. 3by a wire 23 (wire n) wrapped overlying a preceding wire 24 (wire n-l)and having a short end section 26 bonded at 27 to the terminal 13. Astrong, compact terminal and wrapped wire assembly results, wherein ahigh density of wrapped wires is provided on the terminal, wherein eachoverlapping wrapped wire section aids in securing and protecting abonded and compacted end section of an adjacent wire, wherein thebonding of each wire end section allows some degree of strain relief inthe wrapped section of the wire by permitting a relatively loosewrapping operation, and wherein a terminal of circular or othercomerfree cross section may be utilized by virtue of the bonding of thewire end sections to the terminal.

The degree of compactness of the wrapped terminal assembly may be notedby viewing FIGS. 2 and 3. It should be clear that, although each wire11, 17, 21, 23, is wrapped with two turns about the terminal 13, thestructure is such that only one turn separates the positions at whichadjacent pairs of wires come into contact with the terminal. This makesit possible to increase the packaging density to the point at which thespace taken up by each wire connection approximately equals the diameterof an insulated wire.

A special purpose tool, not forming a part of the invention, may beemployed, upon a squeeze of a handle of the tool, to wrap each wireabout the terminal, clamp the end section of the wrapped wire againstthe terminal running axially of the terminal, bond the clamped wire endsection to the terminal, and then release the wire, preparatory toperforming a similar operation on a succeeding wire.

It is to be understood that the described assembly is simplyillustrative of one embodiment of the invention. In other embodimentsoverlapping wire wrap sections may be spaced one from another and/or mayoverlap non-bonded sections of one or more wires, which overlap ed wiresmay be affixed or bonded elsewhere to the terminal or may remainunbonded throughout their entire lengths. Additionally, one or more wireend sections may be secured to the terminal prior to the wrapping ofadjacent sections of the secured wires about the terminal. Manyadditional modifications may be made in accordance with the principlesof the invention.

What is claimed is:

l. A terminal and wrapped wire assembly, comprising:

a tenninal; and

a plurality of wires each having a wrap section and a second section,the second section of each wire extending axially along the terminal andthe wrap section of each wire but one being wrapped about the terminaland over a second section of another of said wires.

2. In the assembly of claim 1:

each wire being affixed to the terminal at a position displaced axiallyfrom the wrap section of the wire.

3. In the assembly of claim 1:

each wire wrap section comprising substantially two turns of wire.

4. In the assembly of claim 1:

each wire wrap section being positioned immediately adjacent to a wrapsection of at least one other of said wires.

5. In the assembly of claim 1:

each wire wrap section being positioned immediately adjacent to a wrapsection of at least one other of said wires and each wire but one beingaffixed to the terminal beneath a second section of an adjacent one ofsaid wires.

6. A terminal and wrapped wire assembly, comprising:

a terminal; and

a plurality of wires each having an end section and a wrap sectionspaced from the end section, the end section of each wire extendingaxially along a different axial portion of the terminal and the wrapsection of each wire being wrapped about an adjacent axial portion ofthe terminal with each wrap section but one overlying the end section ofan adjacent one of said wires.

7. In the assembly of claim 6:

each wire wrap section comprising substantially two turns of wirewrapped about the terminal and each underlying wire end section.

8. In the assembly of claim 6: each wire end section being affixed toits respective axial portion of the terminal.

9. A terminal and wrapped wire assembly, comprising:

a terminal; and

a plurality of wires each having an end section and a wrap sectionspaced from the end section, the end section of each wire being bondedto a different axial portion of the terminal and the wrap section ofeach wire being wrapped about an adjacent axial portion of the terminalwith each wrap section but one overlying the end section of an adjacentone of said wires.

10. in the assembly of claim 9:

each wire wrap section comprising substantially two turns of wirewrapped about the terminal and each underlying wire end section.

1. A terminal and wrapped wire assembly, comprising: a terminal; and aplurality of wires each having a wrap section and a second section, thesecond section of each wire extending axially along the terminal and thewrap section of each wire but one being wrapped about the terminal andover a second section of another of said wires.
 2. In the assembly ofclaim 1: each wire being affixed to the terminal at a position displacedaxially from the wrap section of the wire.
 3. In the assembly of claim1: each wire wrap section comprising substantially two turns of wire. 4.In the assembly of claim 1: each wire wrap section being positionedimmediately adjacent to a wrap section of at least one other of saidwires.
 5. In the assembly of claim 1: each wire wrap section beingpositioned immediately adjacent to a wrap section of at least one otherof said wires and each wire but one being affixed to the terminalbeneath a second section of an adjacent one of said wires.
 6. A terminaland wrapped wire assembly, comprising: a terminal; and a plurality ofwires each having an end section and a wrap section spaced from the endsection, the end section of each wire extending axially along adifferent axial portion of the terminal and the wrap section of eachwire being wrapped about an adjacent axial portion of the terminal witheach wrap section but one overlying the end section of an adjacent oneof said wires.
 7. In the assembly of claim 6: each wire wrap sectioncomprising substantially two turns of wire wrapped about the terminaland each underlying wire end section.
 8. In the assembly of claim 6:each wire end section being affixed to its respective axial portion ofthe terminal.
 9. A terminal and wrapped wire assembly, comprising: aterminal; and a plurality of wires each having an end section and a wrapsection spaced from the end section, the end section of each wire beingbonded to a different axial portion of the terminal and the wrap sectionof each wire being wrapped about an adjacent axial portion of theterminal with each wrap section but one overlying the end section of anadjacent one of said wires.
 10. In the assembly of claim 9: each wirewrap section comprising substantially two turns of wire wrapped aboutthe terminal and each underlying wire end section.